Two-dimensional liquid cell dielectric microscopy

Project Information

Liquid2DM

Grant agreement ID: 819417

DOI

10.3030/819417

EC signature date 20 December 2018

Start date 1 October 2019

End date 30 September 2026

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 998 829,00

EU contribution

€ 1 998 829,00

Coordinated by

THE UNIVERSITY OF MANCHESTER
United Kingdom

Periodic Reporting for period 4 - Liquid2DM (Two-dimensional liquid cell dielectric microscopy)

Reporting period: 2024-04-01 to 2025-09-30

Summary of the context and overall objectives of the project

This project develops a new imaging technology capable of imaging and determining for the first time electric polarization and electrodynamic properties of molecular liquids under confinement on the molecular and atomic scale. These are fundamental physical properties (represented by the dielectric constant or electric permittivity) that describe how matter polarizes in response to an external electric field and, in turn, determine fundamental forces that govern molecular interactions. In practice, they play a crucial role in molecular organization, structuring and functioning. As such, they impact in a wide range of phenomena in a variety of fields, from physical sciences to chemistry and biology. Examples include surface coating and wettability; solid-liquid transitions; water-mediated adsorption and transport of charged ions and molecules; molecular binding; and chemical reactions. Despite their impact, our understanding of these properties has remained limited to macroscopic systems in which molecular information associated to molecular heterogeneities and interfacial effects average out. This is due to the lack of experimental tools able to access them directly on the molecular and atomic scale.

In the last decade, we pioneered the development of Scanning Dielectric Microscopy (SDM), succeeding in probing electric polarization properties of nano-objects and macromolecules as small as few tens of nanometers in size. We achieved that by using the scanning probe microscopy approach – using a nanosized scanning tip as a probe - and through a series of instrumental breakthroughs, which pushed the spatial resolution of standard dielectric spectroscopy from micrometer scale down to the nanoscale. The challenge is now to push the technique down to the atomic level. This is exactly what this project will do.

The overall objective is to push the boundaries of SDM to probe electric polarization and electrodynamics properties of molecular liquids under confinement, with focus on water, electrolytic solutions and biologically relevant molecules, by implementing novel experimental and theoretical approaches. In particular, we will engineer 2D liquid cells made of van der Waals crystals by exploiting the most advanced 2D-materials technology, and we will directly probe the molecular liquids confined inside using the SDM scanning probe.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The team has been developing the dielectric microscopy setups and tools required for the project. New liquids cells made of van der Waals crystals have been fabricated, which enabled the team to probe the dielectric properties of water and other molecular liquids confined inside, despite the disruptions and delays caused by the pandemic in the first part of the action. The team have comprised 5 postdoctoral researchers over the past years, who joined the group of the principal investigator in Manchester to carry out this research.

A new lab space dedicated to this project has been set up, where the two newly developed setups have been installed. They have been designed for the study of dielectric polarization and conductive properties of nanoconfined liquids and molecules. Their construction has been completed and they are now fully operational, as planned, 2D liquid cells made of various 2D crystals were successfully fabricated by the team, by transferring and stacking 2D crystals and using microfabrication techniques. The team has successfully carried out dielectric microscopy experiments of these devices, reaching the first critical objectives of the action. In particular, the team has recently obtained new breakthrough results on confined water, being able to measure for the first time the dielectric properties and conductivity in the in-plane direction – a technical challenge not achieved before. While our previous study reveal confined water is non-polarizable in the out-of-plane direction with respect to the confining surfaces, our recent experiments found that it has enhanced in-plane polarizability and conductivity, reaching superionic levels at room temperature. These findings, published in Nature in October 2025 (see www.nature.com/articles/s41586-025-09558-y) indicate the emergence of a new, 2D water phase characterized by ferroelectric-like polarizability and superionic-like conductivity with profound implications for biology, chemistry and energy science. Our investigation continues, with new results expected to be obtained in the months to come.

The team has disseminated the results related to this action in several peer-review publications and invited talks at international workshops/conferences and on social media.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

We are developing a new microscopy platform able to visualize key physical properties of molecular liquids that has remained unknown so far and with unprecedented resolution. This is achieved by combining two advanced technologies: a novel scanning probe microscopy technique and the 2D-crystal technology available in our group in Manchester. We are applying it to the study of water solutions and biomolecules of major importance in materials and life sciences, but it could also be applied to the study of other solid and liquids.

First results already obtained by the group provided experimental data that were much needed to understand water polarization/electrodynamic properties and water-mediated interactions. This is because despite the advances in atomistic simulations, theorists struggle to predict these properties. The experimental data produced by this action will be key to benchmark their models and theories. In turn, they will help our understanding of the physics of nanoconfined molecular liquids, which is important for developing novel devices for electrochemistry, energy storage and analytical applications.

After the disruptions of the Covid pandemic in the first part of the project, this is now progressing smoothly. We then expect to obtain important new experimental data on the electric polarization/dynamic properties of confined water and biomolecules, such as proteins and DNA, that are crucial in life sciences.

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